Classifier



J. C. STRAUB Jan. 22, 1952 CLASSIFIER 2" srmms-susm 1 Filed Aug. 3 1946 Jan. 22, 1952 J c, STRAUB 2,583,447

CLASSIFIER Filed Aug. 5, 1946 2 SHEETSSI-IEET 2 i 40 I I mm? JOHN C 5778408 ATTORNEYS Patented Jan. 22, 1952 CLASSIFIER John C. Straub, South Bend, Ind., assignor to American Wheelabrator & Equipment Corporation, Mishawaka, Ind., a corporation of Nebraska Application August a, 1946, Serial No. 688,254

' The present invention relates to sorting or elas sifying objects of like sizes from a mixture of different size objects. Although not limited to such use, the invention is particularly applicable .for sorting and classifyii'igmetal shot or abrasive such as used for cleaning, polishing, peening, and the like.

The invention utilizes the principle, inherently present in a pair of meshing gears, that the gap between the teeth increases gradually as the teeth go out of mesh.

According to a preferred embodiment of the invention, the meshing gears constitute a hollow pinion or spur gear working within an annular or. internal gear. To enable them to carry out the invention, the gears are modified by cutting away the roots of the teeth to form open slots between the teeth. Thus each gear comprises spaced annular rings connected by spaced bars which are the teeth. In operation, the material to be graded is fed into the hollow pinion, preferably over the point where the gears engage. The material passes through the pinion slots, then between the ever-widening gaps between the coacting teeth of internal gear and pinion, and thence through the internal gear slots into suitable bins arranged to catch the different size particles. 1

The. invention also consists in certain new an original features and combinations hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be par,- ticularly pointed out in the claims appended hereto, the invention itself, as to its object and advantages, and the manner in which it may be carried out, may be better understood by refer ring to the following description taken in connection with the accompanying drawings. form ing a part hereof, in which:

Fig. 1 is a side elevation of a classifier according to the invention;

Fig. 2 is a vertical section taken on the line Fig. 3 illustrates diagrammatically the classifying action of the mating teeth where the inside circle of the pinion lies inside of the inside circle of the annular gear; and i Fig.4 illustrates diagrammatically the classi fying action of the mating teeth where the inside 4 Claims.' (Cl. 209-98) 2' sure of the invention is made for purposes of explanation, but it will be understood that the details may be modified in various respects without departure from the broad aspect of the invention.

Referring now to the drawings and more particularly to Figs. 1 and 2, the classifier shown for purposes of illustration comprises a frame II] which supports internal gear l8 and pinion.l9. The material to be classified is fed into feed spout 29 whence it passes through the teeth, in a manner explained hereinafter more in detail, into the classifying hoppers 24 from whichit passes through tubes 21 into the bins 28.

. Frame I 0 comprises a horizontal base II, a standard 12 supporting a bearing 36 for a stationary shaft [3. Shaft l3 has a journal I 5 on which is located a ball bearing for rotatably supporting hub 37 of internal gear I8. Nuts l4 adjustably clamp the shaft l3 in stationary position, as explained hereinafter. Shaft l3 has an overhung crank l6 having a journal IT supporting a ball bearing on which is journaled annular Wall 32 of pinion HI.

. Suspended from the shaft I3 is a hanger plate 23 which supports the plurality of hopper cells 24 disposed circumferentially with respect to the annular gear l8 for receiving the different size particles. Each cell 24 has a discharge tube 21 leading to stationary bin 28 which may rest upon the base I I. An adjustable bolt having a thumb nut 25 passes through standard [2 and a slot 26 in hanger 23 for the purpose of circumferentially adjusting the cells 24. The tops of vertical walls of the bins 28 are laid off with shaft I3 as a center to permit adjustment of cells 24. The bins 28 may be any type of a series of containers. 1

It. will be understood that by loosening nuts l4 the position of pinion shaft I! may also be adjusted, circumferentially about internal gear shaft l5, after which nuts M are tightened to clamp the. shaft I! in its adjusted position.

The spur gear I9 is hollow and has wall 32 which connects the ends of teeth 3!. The roots of the teeth 3! are cut away as indicated at 2| except at the ends where material is left forming annular ring 33 and the periphery of wall 32. The teeth 3| thus form spaced bars.

Internal gear l8 has the roots of its teeth 30 cutaway to a depth as indicated by 20, thus forming a plurality of bars connecting end rings 34. and 35. The walls of cells 24 are extended up into the cutaway space as indicated in Fig. 2.. l

Referring nowalso to Fig. 3, the teeth of the gears are shown on a larger scale to illustrate one type of classifying action. Here the tips of teeth .30 of the annular gear l8 are laid. out on inner circle indicated by 4|; the surface formed by cutting away the roots of the teeth 30 coincides with outside circle 43. Similarly, the surface formed by .cutting away the roots of teeth 3| on pinion i9 coincides with inside circle 41 and thetips of teeth 3| coincide with outside circle 49. The pitch circles are denoted by 42 and 48-and are tangent at the pitch point 40.

The teeth of the gears are involute teeth and the line of action 52 is tangent to the base circles (not shown) of the gear and pinion, as will be understood by those skilled in the gear cutting art. Assuming pinion I 9 to be driving annular gear l8, the line of action 52 slopes in the direction indicated. Line 52 passes" through pitch what might be called the first phase of classification. This concerns the region in which the clearance is actually defined as that between T the tips of the pinion teeth 3| and the flanks point 49. As the gears rotate in the direction of arrow K, they engage at the intersection 53 of the inside circle 4| of the annular gear [8 and the line of action 52 and they separate at the intersection 54 of the outside circle 49 of the pinion l9 and the line of action 52. As the'teeth move forward from separation point 54 in the direction of arrow 'K;-the gap between them increases as indicated.

' In the illustration of Fig. 3, the center of pinion I9 is located vertically under the center of annular gear I8 and the feed spout 29 is lo- 'cated on this'vertical line 46 connecting these centers, which also passes through the pitch point 40. l

The material to be classified is fed into feed spout 29 whence it drops upon the inside surface 41 of the pinion 49. This feeding is preferably done in such manner that the particles engage the inside surface of the pinion without shock or rebound. 'The'annu'lar rings 32 and 33 of the pinion l9 provide side retaining walls which prevent the particles from falling out of the pinion.

As'the gears move in the direction of arrow K, the particles pass through the slots between the pinion teeth 3! and become lodged against the tips of annular gear teeth'30 as indicated by through first and the larger particles pass through as' the gaps widen.

A relatively large particle X as shown resting on tooth A has just been delivered to theteeth. It will be-noticed that the space between teeth 'A'and'B has increased to the extent that a smaller particle W has begun todrop into the y-shapedgap between the teeth. At'the positions B 'and'C' the gap has increased so that -small"particle W is just "ready to drop through. Larger particles X is retained until a later position' is reached. At' a position somewhat to the left of 'B and C 'particle'W 'has been; released and is shown dropped'into cell Y. Particle X is still "retained between the teeth in position C and D and finally is shown having dropped intocellV. f It should now "be noted that the gaps between the teeth are ever wideningin the direction of rotation and that there can be no crushing action's'o-long asthe material is fed to the gears at onto the left of the pitch point 40, and so long as care is taken to have the proper relationship betweenfirst and second phase classification, as discussed below.

It will be understood that the other receiving cells receive other sizes,.illustration of which is be apparent from consideration of Figs. 1 and 2. V

of the gear teeth 39. However, it is apparent that at the end of this phase, there is an additional phase represented by the clearance between the tipsof the pinion teeth 3| and the tips of the gear teeth 30.

The second phase may be adjusted to start at any desired point by modifying the inside diametc? of the annular gear 18. If larger sizes of particles are to be separated involving the use of this second phase, care must be taken that it begin before the peak of the first-phase; otherwise there may be a crushing action near the end of the first phase. This same care must be taken even though the second phase is not used for classification, if the material to be classified contains particles larger than the size represented by the peak of the first phase.

The action of the first phase is preferred at the present time for classifying such particles as iron and steel shot and grit for peening and cleaning castings, metal sheets, etc. However, for certain types of materials thesecond phase action may be used, in which case the second phase would be moved toward the pitch point '40 by increasing the inside diameter of the annular gear l8. 'It is possible to use both the first and second phases in one operation if desired, and thus obtain a wider range of classifying sizes. a

Referring now to Fig. '4, here the inside'circle 4|" of the teeth of annular gear [8 is disposed inwardly of the inside circle 4'l' of the teeth of pinion I9. The clearance controlling the classifying action is determined by the inside circle 41' of the pinion and the fiank of the gear teeth 30', the particles being located in pockets, as indicated, at-the left side of the gear teeth 39. As these gaps widen with movement in the direction of the arrow L, the different size particles X and W pass through into the cells below in a manner somewhat similar to that explained in-connection with Fig. 3 and further description will be omitted in the interest of brevity.

In the forms illustrated the gears are moved by hand, i. e. the spur gear I9 is pushed manually. If desired, however, gear 'l8 may be the driving gear; also either gear may be power driven if desired. .7

Additional classifier actions are possible with the teeth relationships of Figs. 3' and 4, such additional actions being obtained by changing the adustment of the pinion journal H, as will Considering, first, Fig. 3; let-it be assumed that the center of pinion shaft I has been shifted to the right in Fig. '1' so that the line 45 connecting gear and pinion centers is oblique and that the feed spout 29and the receiving cells 24 are likewise adjusted to retain their relative positions with respect to .line 46. ,This new relationship of the parts may .still beillustrated by Fig. 3 if it be assumed that the .line 60 represents the horizontalinstead of the, lower edge of the sheet. With this adjustment the particles, instead of'falling into pockets .at the rightside of the annular gear "teeth. 30, as indicated, will fall into the pockets at the'left side of the annular gear teeth 30, in which case the classifying action will take place between the tips of the gear teeth 38 and the flanks of the pinion teeth 3|.

Considering now a similar adjustment for 4, with line 48' shifted to occupy an oblique position, and line (58' indicating horizontal, here the material, instead of lodging as indicated, will lodge in pockets at the right side of the annular gear teeth 3t and the separating action will take place between the tips of the pinion teeth 3i and the flanks of the gear teeth It will be noted that with the first described classifier action of Fig. 3, with the feed spout located on the vertical line 46, and the pinion i 9 as the driver, the classifying action is carried out by the driving surfaces of the teeth; consequently, backlash has no effect on the classifying action. With the annular gear 13 driving, the clearance between the teeth is increased by an amount equal to the normal backlash.

With respect to backlash, the same reasoning applies to all classifier actions described herein. That is to say, where the classifying gap is between the driving sides of the teeth, the sizing is independent of the backlash. Where the classifying gap is between the non-driving sides of the teeth the clearance between the teeth is increased by an amount equal to the normal backlash.

The above description applies to involute gearing but the invention is applicable to other types of gearing, such as epicyclical gearing. The involute type is the preferred form, however, be-

cause the relative motion between the teeth tends to eliminate static friction between the particles and the two surfaces, substituting sliding friction. Sliding friction is in general less than static friction thus promoting passage of the particles through the teeth gaps.

This type of classification has certain advantages. The gears may be out very accurately with a large number of teeth at moderate cost. Furthermore, the continual movement of the tooth surfaces forming the gaps, between which the material passes, tends to reduce friction which in other classifying devices tends to retain smaller particles carrying them along to the larger gaps.

The result of this emcient tooth action is that smaller particles pass between the teeth first, and as those teeth move in the direction of the arrows, larger and larger particles pass through them. Thus, with different sizes being discharged through the teeth at different locations, it is only necessary to place a partition to separate one size from another. In this way, each pair of mating teeth becomes a sorting unit, and each pair of teeth sorts all sizes.

In addition to classifying or sorting a heterogeneous mass of particles, the device may also be used for testing a sample of material for determining the percentage of one or more particle sizes in a mixture. It can also be used for sorting the mixture into component sizes for use in applications which require practical sizes to be within certain tolerance limits.

It is obvious that by changing the number of teeth, the relative size of the gears and various other design factors, a wide vary of characteristics may be obtained with respect to the particle sizes to be accommodated, the accuracy of separation, etc.

While certain novel features of the invention have been disclosed herein, and are pointed out in the annexed claims, it will be understood that d various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

In a classifier for sorting difierent size particles, an internal gear having the roots of its teeth omitted to form tooth-shaped bars with open spaces between the teeth, a spur gear meshing said internal gear and having a hollow interior and having roots of its teeth omitted to form tooth-shaped bars with open spaces between the teeth, a feed spout within said hollow gear feeding material near the pitch point of the gears, a plurality of classifying cells under said internal gear, whereby, as the teeth of said gears separate, they permit particles of different sizes to pass through said open spaces and between the ever-widening gaps into appropriate cells.

.2. In a classifier for sorting different size particles, an internal gear having the roots of its teeth cut away to form tooth-shape bars with open spaces between the teeth, a spur gear meshing said internal gear and having a hollow interior and having the roots of its teeth cut away to form tooth-shape bars, end walls connecting said bars, a feed spout within said hollow interior feeding material near the pitch point of the gears, said end walls acting to retain said particles, a plurality of classifying cells under internal gear and closely fitting the outer circle thereof whereby, as the teeth of said gears separate, they permit particles of different sizes to pass through said open spaces and between the ever widening gaps into appropriate cells.

3. In a classifier for sorting different size particles, an internal gear having the roots of its teeth omitted to form tooth-shape bars with open spaces between the teeth, a spur gear meshing said internal gear and having a hollow interior and having roots of its teeth omitted to form tooth-shape bars, the inside circle of the spur gear teeth being inside of the inside circle of the annular gear teeth, a feed conduit within said hollow spur gear feeding said particles near the pitch point of the gears whereby, as the teeth of said gears separate, they permit particles of different sizes to pass through said open spaces and between ever-widening gaps.

i. In a classifier for sorting different size particles, an internal gear having the roots of its teeth omitted to form tooth-shape bars with open spaces between the teeth, a spur gear meshing said internal gear and having a hollow interior and having roots of its teeth omitted to form tooth-shape bars, the inside circle of the internal gear teeth being inside of the inside circle of the spur gear teeth, a feed conduit within said hollow spur gear feeding said particles near the pitch point of the gears whereby, as the teeth of said gears separate, they permit particles of different sizes to pass through said open spaces and between ever-widening gaps.

JOHN C. STRAUB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 951,082 Kidder Mar. 1, 1910 1,242,034 Pearson Oct. 2, 1917 1,414,156 Ross Apr. 25, 1922 2,207,131 Pellam July 9, 1940 

